Synthesis, Characterization, Antibacterial Properties Of Chitosan And Guanidine-chitosan

Chitin, a renewable resource, widely exists in nature. Chitosan deacetylased fromChitin has unique physical and chemical properties and biological functions. Nowadays,Chitin, Chitosan and its derivatives have attracted much attention in the field of biologicalmaterials.In this thesis, firstly Chitosan was prepared through the deacetylation of Chitin, thenthe Chitosan’s deacetylation degree was86.23%. And then NaNO2was used to degradateChitosan to small molecular weight, and the viscosity average molecular weight of thedegradated Chitosan was60.3kDa.Afterwards, Arginine containing guanidine group was connected to the degradatedChitosan. In this process, EDC/NHS is catalyst, and MES is buffer. Three kinds ofGuanidine-ChitosanⅠ, Ⅱ, Ⅲ of different substitution degree were synthesized bycontrolling the reation time. Elemental analysis revealed that the substitution degree of thethree Guanidine-ChitosanⅠ, Ⅱ, Ⅲ were0.092,0.204,0.350respectively.At last, solid medium coated culture method was used to evaluate the antibacterialproperties of Chitosan and Guanidine-Chitosan. Bacterials used in the last step wereS.aureus, a kind of Gram-positive bacteria and E.coli, a kind of Gram-negative bacteria. Itshows that Guanidine-Chitosan exhibits better antibacterial properties than Chitosan.